Dynamic Range Control/Compression (DRC) reduces the dynamic range of an audio signal by some amount by (1) making soft parts in the audio signal louder; (2) making loud parts in the audio signal softer; or (3) both making soft parts louder and making loud parts softer. A reduced dynamic range may be desirable in several situations, including for audio playback systems that can only reproduce a small dynamic range while maintaining low distortions, listening environments with distracting sounds, and in situations where the listener does not want to distract others.
Although, DRC is an important feature for today's audio codecs, several recent audio codecs do not support DRC. For example, DRC is absent in the Unified Speech and Audio Coding (USAC) standard by the Moving Picture Experts Group (MPEG). Advanced Audio Coding (AAC) incorporates a DRC tool, but this DRC tool has drawbacks, including limited time resolution and aliasing distortions.